Wales boss Warren Gatland has been forced into a late change to his line-up for Saturday's clash with Argentina at the Millennium Stadium.

No.8 Ryan Jones was set to lead the side for a record-equalling 28th time but was withdrawn earlier today due to concerns over a calf injury. As a result, Andy Powell is promoted from the bench to fill the void with Jonathan Thomas added to the replacements and flanker Martyn Williams handed the captaincy.

However, there is better news elsewhere with fullback Lee Byrne, wing Leigh Halfpenny and tight-head prop Adam Jones returning to the Test match stage for the first time since the Six Nations.

Williams' inclusion takes his impressive tally to 99 Test caps for Wales - just one off Gareth Thomas and Stephen Jones' record. Sam Warburton - who captained Wales in their win over England - will sit out the clash along with Dragons No.8 Toby Faletau. Dan Lydiate retains his place in the side.

Adam Jones is back at tight-head having missed both warm-up Tests and will be partnered by Paul James at loose-head and Richard Hibbard at hooker making an all Ospreys front-row. Bradley Davies comes into the second-row engine room alongside Alun Wyn Jones.

The backs see four changes from the line-up which faced England last weekend with Tavis Knoyle starting at scrum-half in place of Mike Phillips. James Hook takes the fly-half reins instead of Rhys Priestland while George North switches wings to make way for the returning Halfpenny. Jamie Roberts switches to 12 with Jonathan Davies taking the outside centre berth.

Worryingly for Wales, however, is the absence of British & Irish Lions prop Gethin Jenkins. He last played for the national side in November 2010 and if selected for the World Cup will go to the tournament with a distinct lack of match action under his belt. On the bench - fly-half Stephen Jones will have the chance to break the Welsh appearance record if he sees any action.

Argentina coach Santiago Phelan has made six changes to the side that started the 78-15 victory over a South American Select XV on August 6 with prop Rodrigo Roncero, hooker Mario Ledesma, lock Patricio Albacete, back-row forward Juan Manuel Leguizamon and Juan Martin Fernandez Lobbe and fly-half Felipe Contepomi all returning to the side.

Contepomi will be partnered by scrum-half Nicolas Vergallo and they will be joined in the backs by new Exeter Chiefs winger Gonzalo Camacho and Leicester Tigers speedster Horacio Agulla. In the centres, Santiago Fernandez lines up alongside Biarritz's Marcelo Bosch - one of 12 players based in the Top 14 in the line-up. Regular first-team centre Gonzalo Tiesi will miss the clash due to a shoulder injury.

The back-row has a familiar look to it with Toulon's Juan Fernandez Lobbe packing down along Juan Manuel Leguizamon and Julio Farias Cabello. In the second-row, the Pumas will look to Patricio Albacete for inspiration and he is joined in the engine room by Manuel Carizza. The experienced loose-head Rodrigo Roncero is joined in the front-row by veteran Mario Ledesma and Juan Figallo.